package com.lei.datastructure.linkedlist;

/**
 * @Author LeiXiaoLei
 * @Date 2022/7/22 11:37
 * @Version 1.0
 */
public class LinkedList<E> {
    private Node dummyHead;
    private int size;

    public LinkedList() {
        dummyHead = new Node(null, null);
        this.size = 0;
    }

    public int getSize() {

        return this.size;
    }

    public boolean isEmpty() {
        return size == 0;
    }

    public void add(int index, E e) {
        if (index < 0 || index > size) throw new IllegalArgumentException("Add failed. Illegal index.");
        Node prev = dummyHead;
        for (int i = 0; i < index; i++) {
            prev = prev.next;
        }
        prev.next = new Node(e, prev.next);
        size++;
    }

    public void addFirst(E e) {
        add(0, e);
    }

    public void addLast(E e) {
        add(size, e);
    }

    public E get(int index) {
        if (index < 0 || index > size) throw new IllegalArgumentException("Get failed. Illegal index.");
        Node cur = dummyHead.next;
        for (int i = 0; i < index; i++) {
            cur = cur.next;
        }
        return cur.e;
    }

    public E getFirst() {
        return get(0);
    }

    public E getLast() {
        return get(size - 1);
    }

    public E remove(int index) {
        if (index < 0 || index > size) throw new IllegalArgumentException("Get failed. Illegal index.");
        Node prev = dummyHead;
        for (int i = 0; i < index; i++) {
            prev = prev.next;
        }
        Node retNode = prev.next;
        prev.next = retNode.next;
        retNode.next = null;
        size--;
        return retNode.e;
    }

    public E removeFirst() {
        return remove(0);
    }

    public E removeLast() {
        return remove(size - 1);
    }

    public void set(int index, E e) {
        if (index < 0 || index > size) throw new IllegalArgumentException("Set failed. Illegal index.");
        Node cur = dummyHead.next;
        for (int i = 0; i < index; i++) {
            cur = cur.next;
        }
        cur.e = e;
    }


    public boolean contains(E e) {
        Node cur = dummyHead.next;
        while (cur != null) {
            if (cur.equals(e)) return true;
            cur = cur.next;
        }
        return false;
    }

    @Override
    public String toString() {
        StringBuilder res = new StringBuilder();
        Node cur = dummyHead.next;
        while (cur != null) {
            res.append(cur).append("->");
            cur = cur.next;
        }
        res.append("NULL");
        return res.toString();
    }

    private class Node {
        public E e;
        public Node next;

        public Node() {
            this(null, null);
        }

        public Node(E e) {
            this(e, null);
        }

        public Node(E e, Node next) {
            this.e = e;
            this.next = next;
        }

        @Override
        public String toString() {
            return e.toString();
        }
    }

    public static void main(String[] args) {
        LinkedList<Integer> linkedList = new LinkedList<>();
        System.out.println(linkedList);
        for (int i = 0; i < 5; i++) {
            linkedList.addLast(i);
            System.out.println(linkedList);
        }
        linkedList.add(2, 666);
        System.out.println(linkedList);
        Integer remove = linkedList.remove(2);
        System.out.println(linkedList);
        linkedList.removeFirst();
        System.out.println(linkedList);
    }
}
